The artificial intelligence firm Asapp, Inc. recently signed a lease at the Durst Organization’s 1 World Trade Center for an 18,000-square-foot pre-built office space on the 83rd floor of the iconic tower.

While observers have touted Midtown South’s emerging “Silicon Alley” as the place to be for technology tenants, four home-grown NYC start-ups have quietly collected 110,000 square feet at this historic, George Post-designed property at Prince Street.